As computer technology continues to advance, electronic components such as central processing units (CPUs) of computers are being made to provide faster operational speed and greater functional capabilities. When a CPU operates at a high speed in a computer enclosure, its temperature increases greatly and dramatically. It is desirable to dissipate the generated heat quickly, for example, by using a heat sink attached to the CPU in the enclosure. This allows the CPU and other electronic components in the enclosure to function within their normal operating temperature ranges, thereby assuring the quality of data management, storage and transfer. Generally, a clip is required for mounting the heat sink to the CPU.
In earlier time, a linear type of wire clip was widely used. However, in many modern applications such as when a large heat sink is used, the linear clip cannot firmly retain the heat sink against the CPU. Subsequently, wider plate-type of clips which have good rigidity were developed. A conventional plate-type clip comprises a central pressing portion for pressing a heat sink which is placed on a CPU, and a pair of locking legs extending from the pressing portion. Each locking leg defines a locking opening for retaining a hook of a connector on which the CPU is mounted to thereby secure the heat sink on the CPU. In assembly, the two locking legs are required to moved outward by a user to thereby allow the locking openings of the legs to retain the hooks of the connector. It is complicated and difficult to move the legs in assembly since it has good rigidity. Furthermore, when large force is applied the locking legs are prone to slide over the hooks to damage the CPU or other electronic components adjacent the CPU.
Subsequently cam-type clips were developed. FIG. 7 shows a pair of conventional cam-type clips 90 and a retention module 97. Each clip 90 comprises an integral bracket 91 and a lever 92 having a cam-shaped end and pivotably attached to the body 91. The bracket 91 has a pair of locking legs 94 formed at opposite ends thereof. Each locking leg 94 has an aperture 95 for retaining a corresponding post 98 of the retention module 97. However, the bracket 91 is integral formed and therefore has a large rigidity. As a result, large force is still needed in operation.